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DT125R FORUM

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  3. Bike lacks power

Bike lacks power

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  • CalumC Calum

    @declan The issue being on the new models the powervalve retards after 8K RPM. Starving the engine of the power.

    Getting an older CDI unit, or an aftermarket one, would rectify this.

    declanD Offline
    declanD Offline
    declan
    wrote on last edited by
    #13

    @Calum but it’s alreday revving freely so surely the cdi isn’t the issue I though if the cdi were restricted it would only rev to 9k like mine

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    • CalumC Offline
      CalumC Offline
      Calum
      wrote on last edited by Calum
      #14

      The later CDIs control the powervalve servo. On crossers, the powervalve is controlled by the gearbox, or by exhaust pressure. On the DT it's controlled via the YPVS CDI. Early models this was separate from the CDI. Later models it was an all in one.

      Always Originate, Never Pirate!

      Ryan FR 1 Reply Last reply
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      • CalumC Calum

        The later CDIs control the powervalve servo. On crossers, the powervalve is controlled by the gearbox, or by exhaust pressure. On the DT it's controlled via the YPVS CDI. Early models this was separate from the CDI. Later models it was an all in one.

        Ryan FR Offline
        Ryan FR Offline
        Ryan F
        wrote on last edited by
        #15

        @Calum Is there a year roughly I would need to buy? and would I need a new loom or would it just be a case of wire it up and it's ready to go?

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        • declanD declan

          @Ryan-F well you have your issue then it’s the powervalve yeah an engine porter should be able to do it no problem, the powervalve should whine as you turn the key if it doesn’t then there’s an issue the valve should be aligned through the exhaust port so that it’s a smooth transition as you look through the exhaust port there should be no step or ridge

          Ryan FR Offline
          Ryan FR Offline
          Ryan F
          wrote on last edited by
          #16

          @declan Yeah the power valve works and wines as I turn the ignition I will have to look into what callum said about an old or aftermarket CDI, I was just scratching my head a little as it all seemed ok

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          • CalumC Offline
            CalumC Offline
            Calum
            wrote on last edited by
            #17

            @declan said in Bike lacks power:

            m

            It's like a 3RM model CDI. But to be honest, just get a Zeeltronic for it. It'll be better in the long run since it will be new, rather than buying something old and potentially faulty.

            https://www.thetuningworks.co.uk/store/product_info.php?products_id=1268

            £165

            Always Originate, Never Pirate!

            Ryan FR 1 Reply Last reply
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            • CalumC Calum

              @declan said in Bike lacks power:

              m

              It's like a 3RM model CDI. But to be honest, just get a Zeeltronic for it. It'll be better in the long run since it will be new, rather than buying something old and potentially faulty.

              https://www.thetuningworks.co.uk/store/product_info.php?products_id=1268

              £165

              Ryan FR Offline
              Ryan FR Offline
              Ryan F
              wrote on last edited by
              #18

              @Calum Ok thank you, do they come with like a base map at least?

              was looking at getting another top end and getting it ported also.

              CalumC 1 Reply Last reply
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              • Ryan FR Ryan F

                @Calum Ok thank you, do they come with like a base map at least?

                was looking at getting another top end and getting it ported also.

                CalumC Offline
                CalumC Offline
                Calum
                wrote on last edited by
                #19

                @Ryan-F Zeeltronic provide an array of maps that you can base yours on. They are more aggressive than the OEM maps. I've just left it as the one they provided. I altered the powervalve timings but that's about it IIRC. Best get the handheld programmer too. I found mine came with some crazy map that was totally inappropriate.

                Always Originate, Never Pirate!

                Ryan FR 1 Reply Last reply
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                • CalumC Calum

                  @Ryan-F Zeeltronic provide an array of maps that you can base yours on. They are more aggressive than the OEM maps. I've just left it as the one they provided. I altered the powervalve timings but that's about it IIRC. Best get the handheld programmer too. I found mine came with some crazy map that was totally inappropriate.

                  Ryan FR Offline
                  Ryan FR Offline
                  Ryan F
                  wrote on last edited by
                  #20

                  @Calum Ah ok thank you for the help, I was looking at the older CDI's but like you said alot of them look crusty and I know what you mean about the zeeltronic that is going to be my next buy 100% I don't want to make the bike crazy or nothing and i don't want mega horsepower I just like the torque and acceleration.

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                  • O Offline
                    O Offline
                    Oisin
                    wrote on last edited by
                    #21

                    Would a pinned powervalve create a loss in power and acceleration? Just wondering thanks

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                    • CalumC Offline
                      CalumC Offline
                      Calum
                      wrote on last edited by
                      #22

                      Depends where you pin it.

                      So it's not a clear cut answer.

                      On an unrestricted CDI a pinned powervalve would be detrimental to performance.

                      On a DTRE/X Ignition, a pinned valve will allow you to rev past 9K.
                      On a CDI where the ignition is severely retarded past 8K then it will be a loss of power all round.

                      If the CDI allows power up the higher revs, but, like the RE/X ignition, retards the powervalve, pinning it open will allow you to get that upper power, sacrificing low end.

                      It's not clear cut. For optimum performance, set it up properly and leave it alone.

                      Always Originate, Never Pirate!

                      O 1 Reply Last reply
                      1
                      • DartyD Offline
                        DartyD Offline
                        Darty
                        wrote on last edited by
                        #23

                        Just on ride ability, I feel it’s slower over all with turning the PV off essentially,

                        That’s where a good expansion pipe really helps,

                        Keep it real

                        1 Reply Last reply
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                        • CalumC Calum

                          Depends where you pin it.

                          So it's not a clear cut answer.

                          On an unrestricted CDI a pinned powervalve would be detrimental to performance.

                          On a DTRE/X Ignition, a pinned valve will allow you to rev past 9K.
                          On a CDI where the ignition is severely retarded past 8K then it will be a loss of power all round.

                          If the CDI allows power up the higher revs, but, like the RE/X ignition, retards the powervalve, pinning it open will allow you to get that upper power, sacrificing low end.

                          It's not clear cut. For optimum performance, set it up properly and leave it alone.

                          O Offline
                          O Offline
                          Oisin
                          wrote on last edited by
                          #24

                          @Calum yea I ok and how do u tell if the cdi is restricted? I have a DT 125r 2005

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                          • CalumC Offline
                            CalumC Offline
                            Calum
                            wrote on last edited by
                            #25

                            Well if the bike lacks power, that's usually a good indication that the bikes restricted. 🤣

                            Always Originate, Never Pirate!

                            O 1 Reply Last reply
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                            • CalumC Calum

                              Well if the bike lacks power, that's usually a good indication that the bikes restricted. 🤣

                              O Offline
                              O Offline
                              Oisin
                              wrote on last edited by
                              #26

                              @Calum haha I get yea. And how would one unrestricted it

                              CalumC 1 Reply Last reply
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                              • O Oisin

                                @Calum haha I get yea. And how would one unrestricted it

                                CalumC Offline
                                CalumC Offline
                                Calum
                                wrote on last edited by Calum
                                #27

                                @Oisin You tried searching?

                                https://dt125r.co.uk/topic/578/derestricting-guide

                                Always Originate, Never Pirate!

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